For the purpose of testing individual components of a turbine engine, for example of a compressor, a turbine, or a combustion chamber, measuring probes or flow measuring probes are used. In this context, the measuring probes may be pressure, temperature, anemometer, or direction measuring probes, among others. The measurement is carried out in a pressurized air or hot gas flow, either directly on the engine or, for example on a cylinder pipe-type test specimen, by means of which existing process conditions or parameters, or process conditions or parameters to be varied, are simulated on a test stand.
In this context, the measuring probes identified as examples often require sensors or measuring feelers, of which several may be arranged with a spacing next to one another in a common plane and angled perpendicularly to the probe axis, for example. The arrangement of at least one sensor or measuring feeler on an arm or within a pipe section of the probe, cantilevered perpendicularly from the probe axis, is also possible, for example. In this context it is difficult to adjust such a probe exactly and quickly to the local measuring position, especially in the context of a zero point compensation relative to the lengthwise axis of the test pipe or housing. Especially the housing must be adjusted so that a measuring sensor or head that is angled perpendicularly from the probe axis also coincides centrally exactly with the lengthwise axis of the test body or housing, and in fact in such a manner that it extends exactly parallel to this lengthwise axis with a radial spacing in the measuring position.
An arrangement has been examined, in which a mounting support for a flow measuring probe is fixable on the outer circumference of a cylindrical test pipe. The measuring probe is arranged on the mounting support so as to be slidable in the direction of its lengthwise axis and rotatable about the lengthwise axis so as to be tunably adjustable to the measuring location. The examined case provides a mechanical-optical zero point alignment. In this context, a light source is connected externally and circumferentially rotatably with an orienting head of the measuring probe. A support stand with an outer plan parallel plate axially spaced from the light source on the light head is arranged on the outer circumference of the test pipe by means of a prism. The correct probe position (null point adjustment) is to be determined by repeated repositioning of the light source (parallax method) relative to three marks of the planar plate.
Besides time consuming and complicated positioning and adjusting processes, the possibility of errors is particularly large in connection with relatively large pipe radii, and is predominantly based on the manual handleability. In this context particular reference is made to the setting angle error in the path of the orienting heading between the light source or probe and the planar plate or support stand, based on respective circumferential relative mounting measurement errors of the probe and of the support stand relative to the common lengthwise axis of the test body.
In repositioning devices that have already been proposed, the repositioning accuracy suffers as a result of the use of toothed gear drives or toothed belts. Furthermore, an operation that is, for example, thermally protected from the test chamber or room is practically impossible. In other words, test runs must often be interrupted as a result of frequently required manual operations.